Ok do this..
First go to the ATI Catalyst control centre.
Then go to the Overdrive option which is right below Avivo Video option.
When you click on the Overdrive icon you will see the Ati overdrive option grey(means you cannot do anything)
Now do this.
Right left of Select GPU to configure you will see the lock option.Please click it and unlock it .
You will get the warning.Ignore and you are set.
More information in addition to the above.
This is right off the ATI website.
Source
a. Right click anywhere on your desktop
b. Left click on the ATI Catalyst™Control Center option
c. Click the View Menu Option
d. Select the Advanced View Option (notice the list of items under Graphics Settings)
e. Select the Overdrive™ option under Graphic Settings
f. Ensure that turn on Overdrive™ is selected
g. Click Apply
* Note: Overdrive™ is not available on all cards